1. Field of the Invention
The invention relates to an electronic device, and more particularly to an electronic device capable of reducing radiation signal interference.
2. Description of the Related Art
As regards the development trend of the integrated circuit, miniaturization and compact design are inevitable trends in this modern life as well as in the future. The wireless electronic products, mobile phones for example, are also in this trend. The space for each component within the mobile phone is therefore reduced.
The mobile phone transmits radiation signals via antenna. In general, the mobile phone with hidden antenna uses the Planar Inverted-F Antenna (PIFA) for signal transmission. The operational length of the PIFA is half of the general antenna's operational length so as to reduce the area occupied by the antenna significantly. In addition, the PIFA is characterized by its low position, and consequently, the objective of concealing the antenna is achieved. Therefore, the PIFA has already been widely applied to various kinds of mobile phones with hidden antenna so as to achieve the objective of reducing the size of the mobile phones.
Referring to FIG. 1, a top view of part of the components of the conventional mobile phone with hidden antenna is shown. The mobile phone 100 includes the PIFA 120, the circuit board 110 and the loud speaker 130. The PIFA 120 is used to transmit radiation signals. The circuit board 110 and the PIFA 120 are separated by a medium material (not shown in the drawings). Air, resilient polystyrene plastic, microwave base and the combination of the foregoing are examples of the medium material. The loud speaker 130 is electrically connected to the circuit board 110 and disposed under the PIFA 120, in order to achieve the goal of saving space.
However, the loud speaker 130 is likely to be interfered by the radiation signals emitted from the PIFA 120 in this configuration. Besides, when the loud speaker 130 is interfered by the radiation signals emitted form the PIFA 120, the radiation signals are very likely to couple with other circuits on the circuit board 110 via the loud speaker 130 resulting in interfering to other circuits. Moreover, when the intensity of the radiation signals imposed on the loud speaker 130 is too strong, the loud speaker 130 even affects the receiving functions of the PIFA 120.